Thermostat



July 25, 1933.

H. A. MANTZ THERMOSTAT Filed July 1, 1931 3 Sheets Sheet July 25, 1933.

H. A. MANTZ \THERMQSTAT Filed July 1, 1931 s Sheets-Sheet 2 lllllllhw" "I I Q/a/OQI .MW/m/U Patented July 2 5, 1933 UNITED STATES PATENT OFFICE- HAROLD A. HANTZ, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO MILWAUKEE GAS SPECIALTY COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN THERMOSTAT Application filed July 1, 1931. Serial in. 548,087.

This invention relates, broadly, to thermostats, and more particularly to thermostats adapted for use in connection with ovens and the like, although its use in this respect is not limited.

I have considered the problem of controlling the temperature of ovens, space heaters and the like and have observed that the installation of such devices usually entails making unsightly openings in the walls of the oven or other enclosure and necessitates the use of pipes, control devices and the like outside of the oven where they interfere with operation of the stove and the oven and pre sent an unsightly appearance. The devices are usualy complicated and expensive to install and maintain.

I have conceived of aheat regulating device which need not project outside the oven above the stove nor need it project in the space in front of the oven. It is readily installed and maintained. The device is simple, reliable and inexpensive.

One object of the present invention is to provide a thermally operated device comprising a heat responsive device, a control or other device adapted to be actuated thereby and a flexible actuating connection between the heat responsive device and the control device or its equivalent,

Another object of the invention is to provide a device sensitive to changes in temperature of anoven or the like, which may be used to regulate a valve located at a dis tance from theheat responsive device, whereby control of the temperature of the oven ma be effected at a distance therefrom.

nother important object of the invention is to provide a device in which the connection between the heat res onsive device and the control device may e carried around corners or other obstructions or located in irregular channels.

Another object of the invention is to provide a device which may be hidden from view and which will not interfere with the opera tion and use of the stove, oven or other heating device. I

Still another object of the invention is to provide a heat control device in which changes in temperature cause rotation of the connecting member between the heat responsive device and the control device,instead of linear movement.

A further object of the invention is to provide a device of the character described which shallbe reliable and inexpensive to operate and maintain and which may be readily and quickly installed and removed.

The foregoing and other objects of the invention, together with their attendant advantages, will be apparent as the invention becomes better understood by reference to the accompanying specification and drawings forming a part thereof, it being premised thatchanges may be made in the various details and the manner of operation within the scope of the appended claims without departing from the spirit and scope of the invention.

In the drawings:

Figure 1 is 'a view in perspective of a gas range to which a thermostatic oven regulator is applied in accordance with my invention;

Figure 2 is a view partly in front elevation and partlyin section of a portion of the range shown in Figure 1 with my oven con trol device installed;

and partly in sectio of my control device shown in Figures and 2. The control mechanism has been shown in section and portions only of the oven have been shown;

Figure 3 is a viewipartly in side elevation Figure 4 is a top plan view of the control mechanism with shown in section; v Figure 5 is a view in horizontal section of the heat responsive device of another embodiment of my invention;

Figure 6 is a view in vertical section of the device shown in Figure 5 and taken along the line 66 thereof;

Figure 7 is a vertical section of the heat responsive element of another embodiment of my invention which is a modified form of the device shown in Figures 5 and 6;

Figure 8 is a view in side elevation of still another embodiment of my invention in which another form of heat responsive device is incorporated;

parts of the valve body Figures 1, 2, 3 and 4 there is shown at generally a gas stove or range in which a portion 11 of the ran e is utilized for burners of the open type an another portion of the range is used for an oven 12 in which one or more oven burners 13 are located. On constructing the above the oven may be placed at the ri ht hand or left hand end thereof, as desire The range or other heating device may be of any desired style. In the present instance, however, I have illustrated my invention as applied to the cabinet type of range in which the control valves 16 for the top burners of the stove and the valve 17 for the oven burner are located or mounted upon a sloping panel 18 at the front of the stove in order that the valves, mixing chambers and piping may be covered.

y control device is comprised essentially of three parts, a heat responsive element 21, a control mechanism 22, and a device 23 for connecting them.

The heat responsive device is preferably located within the oven. The heat responsive device of my control system may be located at any desirable position within the oven but I prefer to provide an opening 28 in the inner wall of the oven at the side adjacent the stove portion of the range, ar-

' ranging walls 30 about the opening 28 and between the inner and outer oven walls A and B and locating the heat responsive device within the chamber so formed. By mounting the device in this position it is out of the way and does not interfere with the use of the oven.

The most convenient location for the control device, both from the standpoint of simplicity of construction and utility of op- I eration, is in a position on the panel 18. It

is very desirable, particularly if enameled sheet material is used for the stove construction, that no openin s be made in the outer wall of the oven. f the parts of the heat control device project outside of the oven above the stove, they are not only unsightly but interfere with the operation of the range. I have therefore conceived of a heat control device which utilizes a'flexible connection, between the heat responsive element and the control mechanism, which may be lead around corners or the like and which is therefore well adapted to be located within the wall of the oven above the level of the stove, but which may be led out of the oven wall at a point below the level of the top of the stove and to the control mechanism 22. The heat responsive element, the connecting mechanism, and the control mechanism are especially constructed, in order that the device will transfer the motion of the heat responsive element to the control device so that the control device may regulate the gas flow to the oven burner.

The heat responsive element preferably comprises a helically wound, bi-metallic element 26 which is fastened, as by means of a screw 27, (Figure 3) at one end, to the portion of the oven wall which forms the lower wall 30 of the recess or de ression 28. The other end of the bi-metalllc element is fastened as by means of bolts 29 to a rod 31 which projects downwardly through the helix 26 and through an opening in the lower wall 30. It may readily be understood that temperature changes in the oven will cause differential expansion of the two elements of the helix 26, thus altering the radius of curvature of the helix to cause rotary motion of the rod 31. y

The helix 26 need not be a bi-metallic strip but may be a material having a higher or lower coeificient of expansion than the rod or may have the same coeflicient of expansion. In any case a greater linear expansion will take place in the helix than in the rod and consequently rotary motion is transmitted to the rod in accordance with the temperature of the oven. A preferred form of this type of heat responsive element is shown in Figure 10.

' The lower end of the rod 31 (Figure 3) is drilled to provide an opening in which a flexible cable 32 may be secured to turn with the rod 31. The cable 32 must be capable of being bent or flexed in any direction but must, in this embodiment of the invention, transmit rotary motion without appreciable lost motion. The cable may be of any desired construction but preferably comprises a tightly wound helix of wire or the like.

The cable 32 is housed within a conduit 33 which may be of any desired construction to permit bending of the conduit in any direction and to afford a housing for the cable 32.

A bushing 25 is provided on which the upper end of the conduit 32 may be secured, and the bushing has an inner flange arranged to coact with a flange on the lower end of rod 31, so that the bushing and conduit may be supported by the rod, and at the same time the rod 31 may rotate with respect to the bushing 25 and conduit 32. The outer flange or the upper end of the bushing 25 is adapted to abut the adjacent end of the conduit 32.

A valve casing 34 (Figures 3 and 4) is provided, having a cylindrical portion 35 the outer part of which is threaded to provide means for securing a threaded bushing 36 to the valve body. A sleeve 38 is rovided which has a flanged inner end a apted to abut against the end of the collar 35 and to be held in place by the coupling member 36. The

. outer end of the sleeve 38 is engaged over the end of the conduit 33 in any suitable manner as by spinning portions of the wall thereof into suitable annular depressions in the conduit;

A washer 41 is disposed between the end of the sleeve and the bushing 36 and affords a. bearing in which a spindle 42 is retatably mounted. The outer end of the spindle 42 is drilled longitudinally to provide means for inserting and fastening the cable 32 therein so that spindle 42 will turn with cable 32 and the inner end of the spindle is drilled and tapped to provide threaded engagement for a screw 43. The inner wall of the cylindrical sleeve 35 inside the valve body is hexagonal in cross-section, and the screw 43 is provided with a hexagonally shaped enlargement 44 to cooperatively engage the sleeve 35 to permit axial movement but not rotational movement of the screw 43. It may readily be understood, therefore, that rotational movement of the bi-metallic element 26 causes rotational movement of the cable 32 and spindle 42. Since the screw 43 has threaded engagement with the spindle but cannot rotate, it is apparent that any rotational movement of the spindle will cause axial movement of the screw 43.

The valve body 34 is provided with a suitable annular flange 46 adapted to constitute a valve seat for the disc valve 47. The disc valve is fastened upon a bushing 48 which is slidably mounted within the inner cylindrical portion 35 of the valve body. The end of the bushing 48 is preferably hexagonal to cooperate with the cylindrical portion 35 and therefore the valve may move axially but cannot rotate. The valve divides the interior of the valve body 34 into two chambers 51 and 52, one of which'chambers v51 is connected by means of suitable conduits 53 (Figure 4), mixing valve 54, and conduits 55 with the oven burner, and the other chamber 52 is connected by a suitable bushing 56 with the gas manifold 57 which leads to the operable valve 17. Y

A second screw 58 is threaded into the valve bushing 48 and bears against a reduced stem portion of the screw 43. A flat stem on the screw 58 projects outwardly into a suitable slotted opening in a tapered shaft 59. The

shaft passes through a suitable valve bod cap '61 which has threaded engagement with the valve body34. The flat stem of the screw 58 cooperates with the slot in 59 to permit notational motion of the screw 58 with the manually rotational motion of the shaft 59 and at the same time axial motion of the screw 58 relative to the shaft 59. A spring 50 is disposed between theshaft 59 and a washer 60 on the stem of the valve 58.

A suitable cover plate or dial 63 which may be ornamental is secured to the cap 61, as by means of screws 64. The ornamental cover plate or dial 63 is graduated (Figure 2) to indicate the various oven operating temperatures. The hub 67 of a suitable handle 67 a is secured to the shaft 59 by means of a screw 68. The hub of the handle 67a is provided with a suitable pointer 67 so that the shaft 59 and the screw 58 may be rotated to a position which will cause the valve 47 tobe raised to the proper position to maintain'the oven temperature at any pre-selected value, as hereinafter explained.

A passageway 71 is provided in the wall of the valve bod 34 and the wall of the chamber 51 is drilled at 72 to afford a by-pass in order that gas may pass from the chamber 52 to the chamber 51 in suflicient quantity to maintain a flame at the oven burner as long as the oven gas flow control valve 17 is open. The flow of gas through the passageways 71 and 72 is controlled by means of a. metering screw 73. A passageway 74, which is similar to the passageway 71, is provided in the valve body 34 at a position which is ref-' erably opposite the passageway 71 an the valve body is drilled with an opening 76 to permit gas to flow through alighter tube 77 which has a torch head 78 at its end so that a flame 79 may be maintained adjacent the orts in the oven burner. The flow of in the tube 77 is controlled by a metering screw 71 having threaded engagement'with the valve body 34.

In operation of the oven, the oven control valve handle 17 is turned to the on position, thus admitting gas into the chamber 52. The gas issuing from the lighter tube 77 is ignited in an suitable manner, thus igniting the gas issumg from the ports of the oven burner. The control valve handle 67 is moved to a position such that the pointer indicates the temperature on dial 63 that is to be maintained at the center of the oven. This movement of the handle 67a causes rotation of the screw 58 in a clockwise direction and the screw moves downwardly against the stem of the screw 43 thereby raising the valve 47 from its seat and permitting gas to flow in increased quantities from the chamber 52 li)nto the chamber 51 and thus to the oven urner.

' As the oven heats up the bi-metallic element causes the keyed screw 43 to move further into the spindle in an axial direction. Since the spring 50 tends to bias the valve 47 toward its seat the valve is moved gradually downward to partially close the passageway between the chambers 52 and 51 and thus reduce the flow of gas in the oven burner. As the temperature of the oven approaches the desired temperature the valve 47 is closed to a greater extent until a balance is reached at the selected oven temperature at which movement of the thermostatic element 26 and spindle 42 no longer occurs.

If the temperature of the oven decreases below the desired temperature by reason of decreased gas pressure or the like, movement of the element 26 and the spindle 42 occurs in a clockwise direction to increase the crosssectional area of the valve opening between the chambers 52 and 51 and thus increase the gas flow in the oven burner to bring the temperature up to the desired value.

If an increase in the temperature of the oven above the desired value occurs, the bi-, metallic element 26 reflects the increase by rotating the spindle 42 in an anti-clockwise direction to lower the valve to decrease the gas flow to the oven burner.

It may readily be understood that my improved ovcn heat control device affords a means of accurate control and regulation of the temperature of oven, or other space or article and that by reason of the flexibility of the connecting means between the control mechanism and the heat responsive device the complete installation maybe hidden or located in any desired position. The oven control mechanism, the burner by-pass control, and the lighter control device are all grouped together and are fed from a common manifold.

It is apparent that my invention is susceptible to a wide range of modifications. Parts of the control mechanism may be simplified or eliminated and devices embodying my invention may be constructed in any desired manner in a wide range of equivalents.

The heat responsive device may be constructed in a number of different ways and Figures 5 to 11, inclusive, are illustrative of some of these modified constructions. In Figures 5, 6 and 7 modified forms of the heat responsive device are shown in which the bi-metallic element 81 is wound in spiral form with one end secured to the wall A of the oven as by means of a screw 82 and the other or inner end secured to a shaft 83 upon which a large spur gear 84 is secured.

The large spur gear 84 is geared to a smaller spur gear 86, which is in turn secured on a shaft 87 into which the flexible cable 32 is fastened. The shafts 83 and 87 and the gears 84 and 86 are mounted within a suitable housing 88 and the housing is secured to the lower wall of the recess in the side of the oven by means of a bushing 89 which is inserted in a suitable opening in the wall 30 and which is fastened to the housing as by means of spot welding, or the like. It may readily be understood that changes in the oven temperature will cause rolling and unrolling of the spirally wound bi-metallic element to cause rotation of the spur gears and. rotary movement of the flexible shaft 32 in accordance with the temperature changes. It is apparent that this embodiment of the heat responsive de vice occupies less space in the oven Wall than the element previously described.

A modified form of the device shown in Figures 5 and 6 is shown in Figure 7. This device utilizes a spirally wound bi metallic element 81a which is of the same construction as the element 81 previously described. This element is secured to the oven wall bymeans of a suitable bracket 82a and the inner end is fastened to a shaft 83a upon which is secured a spur gear 84a. The housing 88d is L-shaped and a crown gear 86a is mounted within the horizontal portion of the housing upon a shaft 87a in which the flexible shaft 32 is secured. The plane of the bi-metallic element and of the vertical portion of the housing are parallel to the walls of the oven and consequently this heat responsive device does not protrude as far into the oven as the device shown in Figures 5 and 6 although it necessitates a slightly greater space in a vertical direction.

Another form of heat responsive device is shown in Figures 8 and 9. In this device the shaft 876 in which the flexible shaft 32 is secured is provided with a horizontally extending-lever arm 86b to which a vertically extending pivot pin 91 is secured. A bimetallic element 81?) in the form of a flat strip is located within a suitable horizontally extending recess in the oven wall and is secured by means of rivets 92 to a suitable bracketSSb which is an extension of a flat plate 80 and which is in turn secured to a suitable bushing 89?). The conduit 33 is fastened within the bushing 89?) in any suitable manner as by spot welding, spinning or the like. A U-shaped member 9.0 is fastened to the free end of the bi-metallic element 81?) as by means of rivets 92 and the open end of the element engages the pin 91. It is apparent that any changes in the temperature of the oven will be reflected by movement of the free ends of the bi-metallic strip 81?) and consequent movement of the pin 91 and lever 86?) to cause rotation of the shaft 87?) and corresponding rotation of the shaft 32 to operate the heat control mechanism.

It is apparent that the device shown in Figures 8 and 9 does not project beyond the wall of the oven and that it occupies a minimum vertical space. The device therefore is I 87a, in which the flexible shaft-32 is fastened, extends vertically within a suitable recess in the wall of the oven. A helically wound wire 810 which preferably is constructed of one metal, is secured to the bushing 890 by means of a suitable bracket 820 at one end and is secured at the other end in a suitable opening 93 in the shaft 87 c. The change in length of the Wire at different temperatures is sufficiently great to cause rotation of the shafts 870 and 32 to effectively control and operate the heat control mechanism.

In another-form of the heat control mechanism the construction is substantially the same as that shown and described in Figure 10 except that a tube 81d filled with a suitable liquid is employed instead of the wire 810. The helically wound tube 81d is secured to the bushing 89d by means of a bracket 8201 in the same manner as the element 810 and the free end of the tube is fastened to the upper end of the shaft 87 d. The expansion and contraction of the liquid within the tube due to changes in temperature causes corresponding deformation of the tube to rotate the .shaft 87 d to operate the heat control mechanism.

It is apparent from the foregoing description and explanation that my device is susceptible to considerable modification by those skilled in the'art. Such modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim as my invention:

1. In a heat control device for an oven a heat responsive element at. the oven, a control mechanism adapted for axial actuating movement and remotely disposed with reference to the heat responsive element and a flexible rotatable connection between the heat responsive element and the control mechanism, and adapted to be rotated by said heat responsive element to actuate said control mechanism.

2. In a heat control system for ovens a heat responsive device located adjacent the oven, a control mechanism locatedat a distance from the oven, means connecting the two devices, the heat responsive device being arranged to cause rotation of the connecting means, said rotation causing axial movement of said control mechanism.

3. In a heat control system a heat responsive device and a control device, flexible-m0- tiontransmitting means therebetween, the heat responsive device having one part which rotates said motion transmitting means in accordance with the temperature changes within theoven and the control device having a part. which moves axially of the control de vice in response to rotation of said motion transmitting means to effect regulation of the oven temperature.

4. In a device for controlling the temperature of heaters aheat responsive device, and

a control device actuated by the heat res onsive device, said control device having exible motion transmitting means adapted to be rotated by the heat responsive member and a valve arranged to be moved toward or away from closed position by rotation of said motion transmitting means.

5. In combination, a gas heater, and means for controlling the flow of gas to the gas heater comprising a thermostat located at the heater, a connecting mechanism operatively attached to the thermostat, and means for regulating the amount of gas supplied to the heater comprising a control mechanism having a part rotated by the connecting mechanism and having a valve arranged to be axially shifted in accordance with the rotary motion of the aforesaid parts.

6. In a heat control device, a valve body, a valve disposed within the body for axial movement, a screw below the valve to raise the valve up off its seat, and a member having threaded engagement with the screw and adapted for rotation in response to temperature changes to lift and lower the valve.

7. In a heat control mechanism, a valve body, a valve disposed within the body adapted for axial movement, a screw below the valve adapted to raise and lower the valve by axial movement thereof, and a spindle having threaded engagement with the screw whereby rotary movement of the spindle due to temperature variations actuates the screw axially to raise and lower the valve from its seat in the valve body.

8. In a heat control mechanism, a valve body, a valve disposed within the body and keyed for axial movement only, a screw below the valve also keyed for axial movement only, a spindle having threaded engagement with the screw and mounted only for rotational movement whereby rotation of the spindle moves the screw axially to raise and lower the valve from its seat, and a second screw having threaded engagement with the valve whereby the second screw may be threaded in and out to determine the initial position of the valve with reference to the first screw.

9. In a heat control mechanism, a valve body, a valve disposed within the body and keyed for axial movement only, a screw below the valve also keyed for axial movement only, a spindle having threaded engagement with the screw and mounted only for rotational movement whereby rotation of the spindle moves the screw axially to raise and lower the valve from its seat, a second screw having threaded engagement with the valve, whereby the second screw may be threaded in and out to determine the initial position of the valve with reference to the first screw, and,

a shaft extending through the top of the valve body and having keyed connection with the second named screw to permit rotation of the second named screw by means of the shaft.

10. In a heat control mechanism, a valve body, a valve disposed within the body and keyed for axial movement only, a screw be- I low the valve also keyed for axial movement only, a spindle having threaded engagement with the screw and mounted only for rotational movement whereby rotation of the spindle moves the screw axially to raise and lower the valve fromg its seat, a second screw having threaded engagement with the valve whereby the second screw may be threaded in and out to determine the initial position of the valve with reference to the first screw, a shaft extending through the top of the valve body and having keyed connection with the second named screw to permit rotation of the second named screw by means of the shaft, a dial secured to the valve body and calibrated in accordance with the temperature setting desired, and a pointer secured to the shaft and adapted for movement over the scale to set the device at the temperature desired.

11. In a gas flow control device for gas burners, a valve body, a valve disposed within the body, a heat responsive device, a part within the valve body arranged to be rotatedby the heat responsive device, a means for raising and lowering the valve in accordance with the position of the heat responsive device, and means for determining the initial position of the valve with regard to the means for raising and lowering the valve.

12. In a heat control device, a control mechanism including a valve, a motion transmitting means connected to said valve and arranged for rotary motion to cause axial shlfting of said valve, a lever secured to the first named means, and a fiat bi-metallic element fixed at one end and arranged to move the lever at the other end.

13. In a device ofthe class described, a control'mechanism, a heat responsive device comprising a helically wound member secured at one end thereof to the oven wall, a shaft mounted for rotation and having the other end of the helically wound membersecured to one end thereof, and a flexible shaft extending through said oven wall for transmitting the rotary motion imparted by the helically wound member to the shaft, from the shaft to theicontrol mechanism.

14. In a device of the class described, a heat control mechanism and a heat responsive device including a helically wound closed tube secured to the oven wall at one end thereof and to the shaft of the control mechanism at the other end thereof, the tube being filled with liquid and being subjected to the temperature of the oven whereby changes in the temperature of the oven cause deformation of the tube to cause rotation of the shaft.

15. In combination, a heat responsive element comprising an axially extending helical ,coil having one end fixed in position, a control mechanism, and a flexible connection extending between the other end of said coil and said control mechanism said connection extending axially of and being connected within the coil at one end thereof.

16. In a device of the class described, a control mechanism, a shaft, a heat responsive element coiled about and extending along gear train and said control mechanism for actuating said control mechanism.

18. In a heat control device, a valve body, a valve axially movable in said body, a screw below the valve to raise the valve from its seat, means threaded into said valve for initially determining the position thereof, and rotating means engaging said screw for raising or lowering said valve in response to temperature changes.

19. In a heat control device, a valve body, a valve axially movable in said body, axially movable means for raising said valve from its seat, and flexible means having threaded engagement with said axially movable means and rotated in accordance with temperature variations to raise or lower said valve.

20. In a heat control device, a valve body, a valve axially movable in said body, selectin means having rotatable connection with said valve for setting said valve in a predetermined position, means in said connection providing for independent axial movement of said valve with respect to said selecting means, and flexible motion transmitting means having engagement with said valve and rotatable in response to temperature variations for raising or lowering said valve from its predetermined position.

21. In a device of the class described, a control mechanism having an axially movable valve therein, a shaft, a heat responsive element spiraled around said shaft and having one end secured thereto, flexible motion transmitting means leading from said valve and adapted to be rotated by said shaft, and means providing for axial movement of said valve upon rotation of said motion transmitting means.

HAROLD MANTZ. 

